Novel roles of c-Met in the survival of renal cancer cells through the regulation of HO-1 and PD-L1 expression

Paired CRISPR screens to map gene regulation in cis and trans

Recent massively-parallel approaches to decipher gene regulatory circuits have focused on the discovery of either cis -regulatory elements (CREs) or trans -acting factors. Here, we develop a scalable approach that pairs cis - and trans -regulatory CRISPR screens to systematically dissect how the key immune checkpoint PD-L1 is regulated. In human pancreatic ductal adenocarcinoma (PDAC) cells, we tile the PD-L1 locus using ∼25,000 CRISPR perturbations in constitutive and IFNγ-stimulated conditions. We discover 67 enhancer- or repressor-like CREs and show that distal CREs tend to contact the promoter of PD-L1 and related genes. Next, we measure how loss of all ∼2,000 transcription factors (TFs) in the human genome impacts PD-L1 expression and, using this, we link specific TFs to individual CREs and reveal novel PD-L1 regulatory circuits. For one of these regulatory circuits, we confirm the binding of predicted trans -factors (SRF and BPTF) using CUT&RUN and show that loss of either the CRE or TFs potentiates the anti-cancer activity of primary T cells engineered with a chimeric antigen receptor. Finally, we show that expression of these TFs correlates with PD-L1 expression in vivo in primary PDAC tumors and that somatic mutations in TFs can alter response and overall survival in immune checkpoint blockade-treated patients. Taken together, our approach establishes a generalizable toolkit for decoding the regulatory landscape of any gene or locus in the human genome, yielding insights into gene regulation and clinical impact.

c-MET and the immunological landscape of cancer: novel therapeutic strategies for enhanced anti-tumor immunity

Cellular mesenchymal-epithelial transition factor (c-MET), also known as hepatocyte growth factor receptor (HGFR), is a crucial receptor tyrosine kinase implicated in various solid tumors, including lung, breast, and liver cancers. The concomitant expression of c-MET and PD-L1 in tumors, such as hepatocellular carcinoma, highlights their prognostic significance and connection to therapeutic resistance. Cancer-associated fibroblasts and mesenchymal stromal cells produce hepatocyte growth factor (HGF), activating c-MET signaling in tumor cells and myeloid-derived suppressor cells (MDSC). This activation leads to metabolic reprogramming and increased activity of enzymes like glutaminase (GLS), indoleamine 2,3-dioxygenase (IDO), and arginase 1 (ARG1), depleting essential amino acids in the tumor microenvironment that are vital for effector immune cell function. This review highlights the interplay between tumor cells and myeloid-derived suppressor cells (MDSCs) that create an immunosuppressive environment while providing targets for c-MET-focused immunotherapy. It emphasizes the clinical implications of c-MET inhibition on the behavior of immune cells such as neutrophils, macrophages, T cells, and NK cells. It explores the potential of c-MET antagonism combined with immunotherapeutic strategies to enhance cancer treatment paradigms. This review also discusses the innovative cancer immunotherapies targeting c-MET, including chimeric antigen receptor (CAR) therapies, monoclonal antibodies, and antibody-drug conjugates, while encouraging the development of a comprehensive strategy that simultaneously tackles immune evasion and enhances anti-tumor efficacy further to improve the clinical prognoses for patients with c-MET-positive malignancies. Despite the challenges and variability in efficacy across different cancer subtypes, continued research into the molecular mechanisms and the development of innovative therapeutic strategies will be crucial.

MACC1 revisited - an in-depth review of a master of metastasis

Cancer metastasis remains the most lethal characteristic of tumors mediating the majority of cancer-related deaths. Identifying key molecules responsible for metastasis, understanding their biological functions and therapeutically targeting these molecules is therefore of tremendous value. Metastasis Associated in Colon Cancer 1 (MACC1), a gene first described in 2009, is such a key driver of metastatic processes, initiating cellular proliferation, migration, invasion, and metastasis in vitro and in vivo. Since its discovery, the value of MACC1 as a prognostic biomarker has been confirmed in over 20 cancer entities. Additionally, several therapeutic strategies targeting MACC1 and its pro-metastatic functions have been developed. In this review, we will provide a comprehensive overview on MACC1, from its clinical relevance, towards its structure and role in signaling cascades as well as molecular networks. We will highlight specific biological consequences of MACC1 expression, such as an increase in stem cell properties, its immune-modulatory effects and induced therapy resistance. Lastly, we will explore various strategies interfering with MACC1 expression and/or its functions. Conclusively, this review underlines the importance of understanding the role of individual molecules in mediating metastasis.

Zanzalintinib (XL092): a next-generation tyrosine kinase inhibitor-comprehensive review of early safety & efficacy data

INTRODUCTION

Zanzalintinib (XL092) is a next-generation anti-VEGFR-related multi-targeted TKI that exhibits immunomodulatory effects.

AREAS COVERED

This review explores preclinical and clinical data, along with the future directions associated with zanzalintinib and its combination with immune checkpoint inhibitors (ICIs).

EXPERT OPINION

In addition to its anti-VEGFR activity, zanzalintinib demonstrates potential synergistic effects with ICIs through its immunomodulatory impact, attributed to its inhibition of MET and TAM kinases. Recent preclinical studies provide compelling evidence supporting this synergistic potential. Furthermore, a recent phase 1 dose escalation study confirmed the tolerability of the zanzalintinib and anti-PDL1 combination without major safety concerns.Multiple ongoing clinical trials are investigating the combination of zanzalintinib and ICIs across various solid tumor types, including phase 3 studies for renal cell carcinoma, colorectal, and head and neck cancer. These trials aim to elucidate the therapeutic role of this new-generation TKI and ICI combination.However, the identification of reliable predictive biomarkers for the zanzalintinib and ICI combination presents significant challenges. Given the intricate nature of their mechanistic rationale and the difficulties in identifying reliable biomarkers for combined anti-angiogenesis and ICI therapies, addressing this challenge remains a priority for ongoing and future research.

Unveiling the Role of HGF/c-Met Signaling in Non-Small Cell Lung Cancer Tumor Microenvironment

Non-small cell lung cancer (NSCLC) is characterized by several molecular alterations that contribute to its development and progression. These alterations include the epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), human epidermal growth factor receptor 2 (HER2), and mesenchymal-epithelial transition factor (c-MET). Among these, the hepatocyte growth factor (HGF)/c-MET signaling pathway plays a crucial role in NSCLC. In spite of this, the involvement of the HGF/c-MET signaling axis in remodeling the tumor microenvironment (TME) remains relatively unexplored. This review explores the biological functions of the HGF/c-MET signaling pathway in both normal and cancerous cells, examining its multifaceted roles in the NSCLC tumor microenvironment, including tumor cell proliferation, migration and invasion, angiogenesis, and immune evasion. Furthermore, we summarize the current progress and clinical applications of MET-targeted therapies in NSCLC and discuss future research directions, such as the development of novel MET inhibitors and the potential of combination immunotherapy.

STELLAR-303: randomized phase III study of zanzalintinib + atezolizumab in previously treated metastatic colorectal cancer

Most patients with metastatic colorectal cancer (mCRC) have limited treatment options following standard-of-care therapy. VEGFR-tyrosine kinase inhibitors (TKIs) have demonstrated clinical activity in mCRC in combination with immune checkpoint inhibitors (ICIs), particularly in patients without liver metastases. The TKI zanzalintinib (XL092) targets VEGFR, MET and TAM kinases, proteins that are involved in tumor growth, angiogenesis, metastasis and immunosuppression. Zanzalintinib has immunomodulatory properties that may enhance response to ICIs. Presented is the design of STELLAR-303, a global, phase III, open-label, randomized study evaluating zanzalintinib plus atezolizumab versus regorafenib in patients with non-MSI-H mCRC who progressed during/after or are refractory/intolerant to standard-of-care therapy. The primary end point is overall survival in patients without liver metastases.Clinical Trial Registration: NCT05425940 (ClinicalTrials.gov).

Therapeutic implications of signaling pathways and tumor microenvironment interactions in esophageal cancer

Esophageal cancer (EC) is significantly influenced by the tumor microenvironment (TME) and altered signaling pathways. Downregulating these pathways in EC is essential for suppressing tumor development, preventing metastasis, and enhancing therapeutic outcomes. This approach can increase tumor sensitivity to treatments, enhance patient outcomes, and inhibit cancer cell proliferation and spread. The TME, comprising cellular and non-cellular elements surrounding the tumor, significantly influences EC's development, course, and treatment responsiveness. Understanding the complex relationships within the TME is crucial for developing successful EC treatments. Immunotherapy is a vital TME treatment for EC. However, the heterogeneity within the TME limits the application of anticancer drugs outside clinical settings. Therefore, identifying reliable microenvironmental biomarkers that can detect therapeutic responses before initiating therapy is crucial. Combining approaches focusing on EC signaling pathways with TME can enhance treatment outcomes. This integrated strategy aims to interfere with essential signaling pathways promoting cancer spread while disrupting factors encouraging tumor development. Unraveling aberrant signaling pathways and TME components can lead to more focused and efficient treatment approaches, identifying specific cellular targets for treatments. Targeting the TME and signaling pathways may reduce metastasis risk by interfering with mechanisms facilitating cancer cell invasion and dissemination. In conclusion, this integrative strategy has significant potential for improving patient outcomes and advancing EC research and therapy. This review discusses the altered signaling pathways and TME in EC, focusing on potential future therapeutics.

Modification of the tumor microenvironment enhances immunity with plasmid gene therapy

Local intratumor delivery with electroporation of low levels of plasmids encoding molecules, induces an antitumor effect without causing systemic toxicity. However, previous studies have predominately focused on the function of the delivered molecule encoded within the plasmid, and ignored the plasmid vector. In this study, we found vectors pUMVC3 and pVax1 induced upregulation of MHC class I (MHC-I) and PD-L1 on tumor cell surface. These molecules participate in a considerable number of immunoregulatory functions through their interactions with and activating inhibitory immune cell receptors. MHC molecules are well-known for their role in antigen (cross-) presentation, thereby functioning as key players in the communication between immune cells and tumor cells. Increased PD-L1 expression on tumor cells is an important monitor of tumor growth and the effectiveness of immune inhibitor therapy. Results from flow cytometry confirmed increased expression of MHC-I and PDL-1 on B16F10, 4T1, and KPC tumor cell lines. Preliminary animal data from tumor-bearing models, B16F10 melanoma, 4T1 breast cancer and KPC pancreatic cancer mouse models showed that tumor growth was attenuated after pUMVC3 intratumoral electroporation. Our data also documented that pSTAT1 signaling pathway might not be associated with plasmid vectors' function of upregulating MHC-I, PD-L1 on tumor cells.

Immune Response and Metastasis-Links between the Metastasis Driver MACC1 and Cancer Immune Escape Strategies

Metastasis remains the most critical factor limiting patient survival and the most challenging part of cancer-targeted therapy. Identifying the causal drivers of metastasis and characterizing their properties in various key aspects of cancer biology is essential for the development of novel metastasis-targeting approaches. Metastasis-associated in colon cancer 1 (MACC1) is a prognostic and predictive biomarker that is now recognized in more than 20 cancer entities. Although MACC1 can already be linked with many hallmarks of cancer, one key process-the facilitation of immune evasion-remains poorly understood. In this review, we explore the direct and indirect links between MACC1 and the mechanisms of immune escape. Therein, we highlight the signaling pathways and secreted factors influenced by MACC1 as well as their effects on the infiltration and anti-tumor function of immune cells.

Comparison of genomic alterations in Epstein-Barr virus-positive and Epstein-Barr virus-negative diffuse large B-cell lymphoma

BACKGROUND

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (EBV-posDLBCL) is an aggressive B-cell lymphoma that often presents similar morphological and immune phenotype features to that of EBV-negative DLBCL (EBV-negDLBCL).

AIMS AND METHODS

To better understand their difference in genomic landscape, we performed whole-exome sequencing (WES) of EBV-posDLBCL and EBV-negDLBCL.

RESULTS

This analysis revealed a new mutational signature 17 (unknown) and signature 29 (smoking) in EBV-posDLBCL as well as a specific mutational signature 24 (associated with aflatoxin) in EBV-negDLBCL. Compared with EBV-negDLBCL, more somatic copy number alterations (CNAs) and deletions were detected in EBV-posDLBCL (p = 0.01). The most frequent CNAs specifically detected in EBV-posDLBCL were gains at 9p24.1 (PDL1 and JAK2), 8q22.2-q24.23 (DEPTOR and MYC), and 7q31.31-q32.2 (MET), which were validated in additional EBV-posDLBCL cases. Overall, 53.7% (22/41) and 62.9% (22/35) of the cases expressed PD-L1 and c-MET, respectively, in neoplastic cells, whereas only 15.4% (4/26) expressed c-MYC. Neoplastic c-MET expression was positively correlated with PD-L1 (p < 0.001) and MYC expression (p = 0.016). However, EBV-posDLBCL cases did not show any differences in overall survival between PD-L1-, c-MET-, or c-MYC-positive and -negative cases or between age-related groups. Analysis of the association between somatic mutation load and EBV status showed no difference in the distribution of tumor mutant burden between the two lymphomas (p = 0.41). Recurrent mutations in EBV-posDLBCL implicated several genes, including DCAF8L1, KLF2, and NOL9, while in EBV-negDLBCL, ANK2, BPTF, and CNIH3 were more frequently mutated. Additionally, PIM1 is the most altered gene in all the WES-detected cases.

CONCLUSIONS

Our results confirm that genomic alteration differs significantly between EBV-posDLBCL and EBV-negDLBCL, and reveal new genetic alterations in EBV-posDLBCL. The positive correlation of c-MET and PD-L1/c-Myc expression may be involved in the pathogenesis of EBV-posDLBCL, which is should be explored prospectively in trials involving MET-directed therapies.

Updated systematic review and network meta-analysis of first-line treatments for metastatic renal cell carcinoma with extended follow-up data

Immune checkpoint inhibitor (ICI)-based combination therapies are the recommended first-line treatment for metastatic renal cell carcinoma (mRCC). However, no head-to-head phase-3 randomized controlled trials (RCTs) have compared the efficacy of different ICI-based combination therapies. Here, we compared the efficacy of various first-line ICI-based combination therapies in patients with mRCC using updated survival data from phase-3 RCTs. Three databases were searched in June 2023 for RCTs that analyzed oncologic outcomes in mRCC patients treated with ICI-based combination therapies as first-line treatment. A network meta-analysis compared outcomes including overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and complete response (CR) rate. Subgroup analyses were based on the International mRCC Database Consortium risk classification. The treatment ranking analysis of the entire cohort showed that nivolumab + cabozantinib (81%) had the highest likelihood of improving OS, followed by nivolumab + ipilimumab (75%); pembrolizumab + lenvatinib had the highest likelihood of improving PFS (99%), ORR (97%), and CR (86%). These results remained valid even when the analysis was limited to patients with intermediate/poor risk, except that nivolumab + ipilimumab had the highest likelihood of achieving CR (100%). Further, OS benefits of ICI doublets were not inferior to those of ICI + tyrosine kinase inhibitor combinations. Recommendation of combination therapies with ICIs and/or tyrosine kinase inhibitors based on survival benefits and patient pretreatment risk classification will help advance personalized medicine for mRCC.

Pharmacological features, health benefits and clinical implications of honokiol

Honokiol (HNK) is a natural polyphenolic compound extracted from the bark and leaves of Magnolia grandiflora. It has been traditionally used as a medicinal compound to treat inflammatory diseases. HNK possesses numerous health benefits with a minimal level of toxicity. It can cross the blood-brain barrier and blood-cerebrospinal fluid, thus having significant bioavailability in the neurological tissues. HNK is a promising bioactive compound possesses neuroprotective, antimicrobial, anti-tumorigenic, anti-spasmodic, antidepressant, analgesic, and antithrombotic features . HNK can prevent the growth of several cancer types and haematological malignancies. Recent studies suggested its role in COVID-19 therapy. It binds effectively with several molecular targets, including apoptotic factors, chemokines, transcription factors, cell surface adhesion molecules, and kinases. HNK has excellent pharmacological features and a wide range of chemotherapeutic effects, and thus, researchers have increased interest in improving the therapeutic implications of HNK to the clinic as a novel agent. This review focused on the therapeutic implications of HNK, highlighting clinical and pharmacological features and the underlying mechanism of action.Communicated by Ramaswamy H. Sarma.

MET Receptor Tyrosine Kinase Inhibition Reduces Interferon-Gamma (IFN-γ)-Stimulated PD-L1 Expression through the STAT3 Pathway in Melanoma Cells

Melanoma is the leading cause of death from cutaneous malignancy. While targeted therapy and immunotherapy with checkpoint inhibitors have significantly decreased the mortality rate of this disease, advanced melanoma remains a therapeutic challenge. Here, we confirmed that interferon-gamma (IFN-γ)-induced PD-L1 expression in melanoma cell lines. This increased expression was down-regulated by the reduction in phosphorylated STAT3 signaling via MET tyrosine kinase inhibitor treatment. Furthermore, immunoprecipitation and confocal immunofluorescence microscopy analysis reveals MET and PD-L1 protein-protein interaction and colocalization on the cell surface membrane of melanoma cells. Together, these findings demonstrate that the IFN-γ-induced PD-L1 expression in melanoma cells is negatively regulated by MET inhibition through the JAK/STAT3 signaling pathway and establish the colocalization and interaction between an RTK and a checkpoint protein in melanoma cells.

Clinical Outcomes of Cabozantinib in Patients Previously Treated with Atezolizumab/Bevacizumab for Advanced Hepatocellular Carcinoma-Importance of Good Liver Function and Good Performance Status

(1) Background: This study aimed to investigate clinical outcomes for cabozantinib in clinical practice in patients with advanced hepatocellular carcinoma (HCC) previously treated with atezolizumab plus bevacizumab (Atz/Bev), with a focus on whether patients met criteria of Child-Pugh Class A and Eastern Cooperative Oncology Group performance status (ECOG-PS) score 0/1 at baseline. (2) Methods: Eleven patients (57.9%) met the criteria of both Child-Pugh class A and ECOG-PS score 0/1 (CP-A+PS-0/1 group) and eight patients (42.1%) did not (Non-CP-A+PS-0/1 group); efficacy and safety were retrospectively evaluated. (3) Results: Disease control rate was significantly higher in the CP-A+PS-0/1 group (81.1%) than in the non-CP-A+PS-0/1 group (12.5%). Median progression-free survival, overall survival and duration of cabozantinib treatment were significantly longer in the CP-A+PS-0/1 group (3.9 months, 13.4 months, and 8.3 months, respectively) than in the Non-CP-A+PS-0/1 group (1.2 months, 1.7 months, and 0.8 months, respectively). Median daily dose of cabozantinib was significantly higher in the CP-A+PS-0/1 group (22.9 mg/day) than in the non-CP-A+PS-0/1 group (16.9 mg/day). (4) Conclusions: Cabozantinib in patients previously treated with Atz/Bev has potential therapeutic efficacy and safety if patients have good liver function (Child-Pugh A) and are in good general condition (ECOG-PS 0/1).

HMOX1 pathway signature predicts clinical benefit from immunotherapy plus tyrosine kinase inhibitor therapy in advanced renal cell carcinoma

BACKGROUND

Immunotherapy (IO) plus tyrosine kinase inhibitor (TKI) emerged as standard first-line therapy for advanced renal cell carcinoma (RCC). The heme Oxygenase 1 (HMOX1) pathway is involved in tumor development and treatment resistance, which may affect the efficacy of TKI + IO.

METHODS

Two cohorts from our center (ZS-MRCC, ZS-HRRCC), one cohort from clinical trial (JAVELIN Renal 101) and the Cancer Genome Atlas (TCGA-KIRC) were enrolled. HMOX1 pathway signatures were determined for each sample by RNA-sequencing and gene set enrichment analysis. Immune infiltration was evaluated by flow cytometry. Response and progression-free survival (PFS) were set as primary endpoints.

RESULTS

Patients of low-HMOX1 signature showed higher objective response rate (43.5% vs. 27.3%) in ZS-MRCC cohort and longer PFS in both cohorts (ZS-MRCC cohort, p = 0.019; JAVELIN-101 cohort, p = 0.036). Patients in the high-HMOX1 signature arm also showed greater clinical benefit from TKI + IO, rather than TKI monotherapy (p < 0.001). In high-HMOX1 signature RCC tissues, CD8⁺ T cells showed a dysfunctional phenotype with decreased GZMB expression (Spearman's ρ = -0.32, p = 0.045). A risk score based on HMOX1 signature was further constructed by random forest approach, involving HMOX1 signature and immunologic features. In patients with a low risk level, TKI + IO combination therapy demonstrated longer PFS than TKI monotherapy (p < 0.001), however in individuals with a high risk score group, these two regimens did not give different advantages.

CONCLUSIONS

Our study identified the HMOX1 pathway signature was a potential prognostic factor of progression-free survival for TKI + IO combination therapy in the advanced RCC in different cohort, especially in first-line management of mRCC in the Javelin 101 cohort. Moreover, HMOX1 signature was associated with T-cell function in tumor environment.

Phase II Study Investigating the Safety and Efficacy of Savolitinib and Durvalumab in Metastatic Papillary Renal Cancer (CALYPSO)

PURPOSE

Metastatic papillary renal cancer (PRC) has poor outcomes, and new treatments are required. There is a strong rationale for investigating mesenchymal epithelial transition receptor (MET) and programmed cell death ligand-1 (PD-L1) inhibition in this disease. In this study, the combination of savolitinib (MET inhibitor) and durvalumab (PD-L1 inhibitor) is investigated.

METHODS

This single-arm phase II trial explored durvalumab (1,500 mg once every four weeks) and savolitinib (600 mg once daily; ClinicalTrials.gov identifier: NCT02819596). Treatment-naïve or previously treated patients with metastatic PRC were included. A confirmed response rate (cRR) of > 50% was the primary end point. Progression-free survival, tolerability, and overall survival were secondary end points. Biomarkers were explored from archived tissue (MET-driven status).

RESULTS

Forty-one patients treated with advanced PRC were enrolled into this study and received at least one dose of study treatment. The majority of patients had Heng intermediate risk score (n = 26 [63%]). The cRR was 29% (n = 12; 95% CI, 16 to 46), and the trial therefore missed the primary end point. The cRR increased to 53% (95% CI, 28 to 77) in MET-driven patients (n/N = 9/27) and was 33% (95% CI, 17 to 54) in PD-L1-positive tumors (n/N = 9/27). The median progression-free survival was 4.9 months (95% CI, 2.5 to 10.0) in the treated population and 12.0 months (95% CI, 2.9 to 19.4) in MET-driven patients. The median overall survival was 14.1 months (95% CI, 7.3 to 30.7) in the treated population and 27.4 months (95% CI, 9.3 to not reached [NR]) in MET-driven patients. Grade 3 and above treatment related adverse events occurred in 17 (41%) patients. There was 1 grade 5 treatment-related adverse event (cerebral infarction).

CONCLUSION

The combination of savolitinib and durvalumab was tolerable and associated with high cRRs in the exploratory MET-driven subset.

Downstream Targets of VHL/HIF-α Signaling in Renal Clear Cell Carcinoma Progression: Mechanisms and Therapeutic Relevance

The clear cell variant of renal cell carcinoma (ccRCC) is the most common renal epithelial malignancy and responsible for most of the deaths from kidney cancer. Patients carrying inactivating mutations in the Von Hippel-Lindau (VHL) gene have an increased proclivity to develop several types of tumors including ccRCC. Normally, the Hypoxia Inducible Factor alpha (HIF-α) subunits of the HIF heterodimeric transcription factor complex are regulated by oxygen-dependent prolyl-hydroxylation, VHL-mediated ubiquitination and proteasomal degradation. Loss of pVHL function results in elevated levels of HIF-α due to increased stability, leading to RCC progression. While HIF-1α acts as a tumor suppressor, HIF-2α promotes oncogenic potential by driving tumor progression and metastasis through activation of hypoxia-sensitive signaling pathways and overexpression of HIF-2α target genes. One strategy to suppress ccRCC aggressiveness is directed at inhibition of HIF-2α and the associated molecular pathways leading to cell proliferation, angiogenesis, and metastasis. Indeed, clinical and pre-clinical data demonstrated the effectiveness of HIF-2α targeted therapy in attenuating ccRCC progression. This review focuses on the signaling pathways and the involved genes (cyclin D, c-Myc, VEGF-a, EGFR, TGF-α, GLUT-1) that confer oncogenic potential downstream of the VHL-HIF-2α signaling axis in ccRCC. Discussed as well are current treatment options (including receptor tyrosine kinase inhibitors such as sunitinib), the medical challenges (high prevalence of metastasis at the time of diagnosis, refractory nature of advanced disease to current treatment options), scientific challenges and future directions.

The Gut Microbiome and Metastatic Renal Cell Carcinoma

The introduction of targeted therapy (TT) and immuno-oncology (IO) agents have revolutionized the treatment of metastatic renal cell carcinoma (mRCC). However, despite the significant improvements in survival and clinical response yielded by these agents, a significant percentage of patients still experience progressive disease. Evidence now suggests that microorganisms living in the gut (i.e., the gut microbiome) could be used as a biomarker for response and may also have utility in increasing response to these treatments. In this review, we present an overview of the role of the gut microbiome in cancer and its potential implications in the treatment of mRCC.

Preclinical Characterization of XL092, a Novel Receptor Tyrosine Kinase Inhibitor of MET, VEGFR2, AXL, and MER

The multi-receptor tyrosine kinase inhibitor XL092 has been developed to inhibit the activity of oncogenic targets, including MET, VEGFR2, and the TAM family of kinases TYRO3, AXL and MER. Presented here is a preclinical evaluation of XL092. XL092 causes a significant decrease in tumor MET and AXL phosphorylation (P < 0.01) in murine Hs 746T xenograft models relative to vehicle, and a 96% inhibition of VEGFR2 phosphorylation in murine lungs. Dose-dependent tumor growth inhibition with XL092 was observed in various murine xenograft models, with dose-dependent tumor regression seen in the NCI-H441 model. Tumor growth inhibition was enhanced with the combination of XL092 with anti-PD-1, anti-programmed death ligand-1 (PD-L1), or anti-CTLA-4 compared with any of these agents alone in the MC38 murine syngeneic model and with anti-PD-1 in the CT26 colorectal cancer survival model. In vivo, XL092 promoted a decrease in the tumor microvasculature and significant increases of peripheral CD4+ T cells and B cells and decreases in myeloid cells versus vehicle. Significant increases in CD8+ T cells were also observed with XL092 plus anti-PD-1 or anti-PD-L1 versus vehicle. In addition, XL092 promoted M2 to M1 repolarization of macrophages in vitro and inhibited primary human macrophage efferocytosis in a dose-dependent manner. In summary, XL092 was shown to have significant antitumor and immunomodulatory activity in animal models both alone and in combination with immune checkpoint inhibitors, supporting its evaluation in clinical trials.

Immunosuppressive tumor microenvironment modulation by chemotherapies and targeted therapies to enhance immunotherapy effectiveness

With the rapid clinical development of immune checkpoint inhibitors (ICIs), the standard of care in cancer management has evolved rapidly. However, immunotherapy is not currently beneficial for all patients. In addition to intrinsic tumor factors, other etiologies of resistance to ICIs arise from the complex interplay between cancer and its microenvironment. Recognition of the essential role of the tumor microenvironment (TME) in cancer progression has led to a shift from a tumor-cell-centered view of cancer development, to the concept of a complex tumor ecosystem that supports tumor growth and metastatic dissemination. The expansion of immunosuppressive cells represents a cardinal strategy deployed by tumor cells to escape detection and elimination by the immune system. Regulatory T lymphocytes (Treg), myeloid-derived suppressor cells (MDSCs), and type-2 tumor-associated macrophages (TAM2) are major components of these inhibitory cellular networks, with the ability to suppress innate and adaptive anticancer immunity. They therefore represent major impediments to anticancer therapies, particularly immune-based interventions. Recent work has provided evidence that, beyond their direct cytotoxic effects on cancer cells, several conventional chemotherapeutic (CT) drugs and agents used in targeted therapies (TT) can promote the elimination or inactivation of suppressive immune cells, resulting in enhanced antitumor immunity. In this review, we will analyze findings pertaining to this concept, discuss the possible molecular bases underlying the selective targeting of these immunosuppressive cells by antineoplastic agents (CT and/or TT), and consider current challenges and future prospects related to the integration of these molecules into more efficient anticancer strategies, in the era of immunotherapy.

Significant role of savolitinib in a case of advanced gastric cancer with abnormal mesenchymal-epithelial transition factor (MET): A case report

RATIONALE

Gastric cancer is a common and lethal malignancy worldwide. It lacks specific clinical symptoms during the early stages, and when detected, the optimal surgical opportunity is lost. Chemotherapy alone offers limited benefits in advanced inoperable disease or postoperative recurrence. Gastric cancer is a heterogeneous tumor involving multiple gene regulations; thus, multi-target combination therapy is the trend in research. The c-MET protein is a tyrosine kinase receptor belonging to the MET family, encoded by the MET proto-oncogene. After binding with its ligand, the hepatocyte growth factor, MET activates cellular signaling pathways in proliferation, motility, migration, and invasion. In addition, it may be abnormally activated in cancers via mutation, amplification, and protein overexpression.

PATIENT CONCERNS AND DIAGNOSIS

We report a 35-year-old male with advanced gastric cancer and bone metastasis who was intolerant to chemotherapy. He was in poor general condition, with thrombocytopenia and anemia.

INTERVENTIONS AND OUTCOME

Next-generation sequencing (NGS) suggested MET gene amplification in the tumor. After savolitinib treatment, the condition improved significantly without noticeable adverse reactions and maintained a progression-free status for 14 weeks.

LESSONS

This case report provides evidence for MET tyrosine kinase inhibitors in treating gastric cancer patients with MET gene amplification. It also shows that MET detection is a target in gastric cancer.

Macrophage Gal/GalNAc lectin 2 (MGL2)+ peritoneal antigen presenting cells during Fasciola hepatica infection are essential for regulatory T cell induction

Fasciola hepatica, one of the agents that causes fasciolosis, modulates the host immune system to allow parasite survival in the host. F. hepatica expresses carbohydrate-containing glycoconjugates that are decoded by C-type lectin receptors, such as Dectin-1, mannose receptor, DC-SIGN and MGL, that are mainly present on myeloid antigen presenting cells (APCs) and can mediate immunoregulatory properties on T cells. In particular, Macrophage Gal/GalNAc lectin 2 (MGL2) expands modified Th2 immune responses, while suppressing Th1 polarization, upon recognition of GalNAc-glycosylated parasite components. In this study, by using MGL2-DTR transgenic mice that encode human diphtheria toxin receptor in MGL2⁺ cells, we demonstrate the role of peritoneal APCs during F. hepatica infection in favoring parasite survival. This process might be mediated by the induction of splenic Tregs in vivo, since the depletion of MGL2⁺ cells conferred mice with partial resistance to the infection and abrogated the increase of CD4⁺/CD25⁺ FoxP3⁺ Tregs induced by the parasite. Therefore, MGL2⁺ cells are critical determinants of F. hepatica infection and could constitute immune checkpoints to control parasite infection.

Regulatory T-cells-related signature for identifying a prognostic subtype of hepatocellular carcinoma with an exhausted tumor microenvironment

Regulatory T-Cells (Tregs) are important in the progression of hepatocellular cancer (HCC). The goal of this work was to look into Tregs-related genes and develop a Tregs-related prognostic model. We used the weighted gene co-expression network analysis (WGCNA) to look for Tregs-related genes in the TCGA, ICGC, and GSE14520 cohorts and then used the non-negative matrix factorization (NMF) algorithm to find Tregs-related subpopulations. The LASSO-Cox regression approach was used to determine Tregs-related genes, which were then condensed into a risk score. A total of 153 overlapping genes among the three cohorts were considered Tregs-related genes. Based on these genes, two Tregs-associated clusters that varied in both prognostic and biological characteristics were identified. When compared with Cluster 1, Cluster 2 was a TME-exhausted HCC subpopulation with substantial immune cell infiltration but a poor prognosis. Five Tregs-related genes including HMOX1, MMP9, CTSC, SDC3, and TNFRSF11B were finally used to construct a prognostic model, which could accurately predict the prognosis of HCC patients in the three datasets. Patients in the high-risk scores group with bad survival outcomes were replete with immune/inflammatory responses, but exhausted T cells and elevated PD-1 and PD-L1 expression. The results of qRT-PCR and immunohistochemical staining (IHC) analysis in clinical tissue samples confirmed the above findings. Moreover, the signature also accurately predicted anti-PD-L1 antibody responses in the IMvigor210 dataset. Finally, HMOX1, MMP9, and TNFRSF11B were expressed differently in Hep3B and Huh7 cells after being treated with a PD1/PD-L1 inhibitor. In conclusion, our study uncovered a Tregs-related prognostic model that could identify TME- exhausted subpopulations and revealed that PD1/PD-L1 inhibitors could alter the expression levels of HMOX1, MMP9, and TNFRSF11B in Hep3B and Huh7 cells, which might help us better understand Tregs infiltration and develop personalized immunotherapy treatments for HCC patients.

c-Met Signaling as a Therapeutic Target in Head and Neck Cancer

ABSTRACT

Despite a dearth of activating driver mutations in head and neck squamous cell carcinoma (HNSCC), aberrant activation of the oncogenes, epidermal growth factor receptor (EGFR), and c-Met is near-universal in human papillomavirus (HPV)-negative disease. Although EGFR activation drove the successful development of the anti-EGFR monoclonal antibody cetuximab in HNSCC, no c-Met-targeting therapy has gained regulatory approval. Inhibition of the c-Met pathway may subvert oncogenesis within the tumor-intrinsic compartment, blocking tumoral proliferation, invasion, migration, and metastasis, or the tumor-extrinsic compartment, modulating the immunosuppressive tumor microenvironment. This review discusses the rationale and current drug development strategies for targeting c-Met or its exclusive ligand hepatocyte growth factor (HGF) in HNSCC.

Targeting of c-MET and AXL by cabozantinib is a potential therapeutic strategy for patients with head and neck cell carcinoma

Local or metastatic relapse following surgery, radiotherapy, and cisplatin is the leading cause of death in patients with head and neck squamous cell carcinoma (HNSCC). Our study shows overexpression of c-MET and AXL in HNSCC cells and patients resistant to radiotherapy and cisplatin. We demonstrate that cabozantinib, an inhibitor of vascular endothelial growth factor receptor (VEGFR), c-MET, and AXL, decreases migration, invasion, and proliferation and induces mitotic catastrophe and apoptotic cell death of naive and radiotherapy- and cisplatin-resistant HNSCC cells. Cabozantinib inhibits the growth and metastatic spread of experimental HNSCC in zebrafish and the growth of experimental HNSCC in mice by blocking tumor cell proliferation and angiogenesis. The efficacy of cabozantinib is also confirmed on viable sections of surgically removed specimens of human HNSCC and on a patient who relapses after five lines of treatment. These results suggest that cabozantinib is relevant for the treatment of patients with HNSCC after relapse under radiotherapy and cisplatin.

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AXL and c-MET are overexpressed in radiotherapy- and cisplatin-resistant HNSCC

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Overexpression of AXL and c-MET contributes to tumor aggressiveness and poor prognosis

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Cabozantinib has anti-tumor and anti-metastatic efficacy in mice and zebrafish models

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Cabozantinib efficacy is shown on HNSCC biopsies and in one patient after several relapses

A review of PD-1/PD-L1 siRNA delivery systems in immune T cells and cancer cells

OBJECTIVES

Programmed cell death 1 (PD-1) is a member of the CD28/CTLA-4 family of inhibitory immunological checkpoint receptors that's also widely produced by exhausted T lymphocytes in an immunosuppressive tumor microenvironment. PD-1 binds to programmed death ligand (PD-L1) and suppresses anti-cancer activity of T lymphocytes. We examined the current literature on how siRNA delivery systems can be used to target PD-1 and PD-L1, as well as the anti-cancer mechanisms and challenges associated with siRNA molecules. We look at studies that use program death 1 siRNA or program death 1 ligand siRNA to treat cancer. Several databases have been used for this purpose, including NCBI, Scopus, and Google Scholar.

KEY FINDINGS

This study looked at several methods for delivering siRNA to immune cells and cancer cells. According to these findings, suppressing PD-1 in T cells increases T lymphocyte activity. PD-L1 suppression in DCs improves antigen presentation and co-stimulatory signals on their surface, resulting in T cell activation. Chemotherapy resistance and cancer cell suppression of T cells are reduced when PD-L1/2 is suppressed in cancer cells.

CONCLUSION

The findings of this study indicated that several strategies for siRNA transfection to immune and cancer cells have been evaluated in recent decades, some of which effectively transfect siRNA to target cells, and defined PD-1 siRNA as a promising strategy for cancer treatment.

Opportunities and challenges of targeting c-Met in the treatment of digestive tumors

At present, a large number of studies have demonstrated that c-Met generally exerts a crucial function of promoting tumor cells proliferation and differentiation in digestive system tumors. c-Met also mediates tumor progression and drug resistance by signaling interactions with other oncogenic molecules and then activating downstream pathways. Therefore, c-Met is a promising target for the treatment of digestive system tumors. Many anti-tumor therapies targeting c-Met (tyrosine kinase inhibitors, monoclonal antibodies, and adoptive immunotherapy) have been developed in treating digestive system tumors. Some drugs have been successfully applied to clinic, but most of them are defective due to their efficacy and complications. In order to promote the clinical application of targeting c-Met drugs in digestive system tumors, it is necessary to further explore the mechanism of c-Met action in digestive system tumors and optimize the anti-tumor treatment of targeting c-Met drugs. Through reading a large number of literatures, the author systematically reviewed the biological functions and molecular mechanisms of c-Met associated with tumor and summarized the current status of targeting c-Met in the treatment of digestive system tumors so as to provide new ideas for the treatment of digestive system tumors.

The Conformational Transition Pathways and Hidden Intermediates in DFG-Flip Process of c-Met Kinase Revealed by Metadynamics Simulations

Protein kinases intrinsically translate their conformations between active and inactive states, which is key to their enzymatic activities. The conformational flipping of the three-residue conservative motif, Asp-Phe-Gly (DFG), is crucial for many kinases' biological functions. Obtaining a detailed demonstration of the DFG flipping process and its corresponding dynamical and thermodynamical features could broaden our understanding of kinases' conformation-activity relationship. In this study, we employed metadynamics simulation, a widely used enhanced sampling technique, to analyze the conformational transition pathways of the DFG flipping for the c-Met kinase. The corresponding free energy landscape suggested two distinct transition pathways between the "DFG-in" and "DFG-out" states of the DFG-flip from c-Met. On the basis of the orientation direction of the F1223 residue, we correspondingly named the two pathways the "DFG-up" path, featuring forming a commonly discovered "DFG-up" transition state, and the "DFG-down" path, a unique transition pathway with F1223 rotating along the opposite direction away from the hydrophobic cavity. The free energies along the two pathways were then calculated using the Path Collective Variable (PCV) metadynamics simulation. The simulation results showed that, though having similar free energy barriers, the free energy cuve for the DFG-down path suggested a two-step conformational transition mechanism, while that for the DFG-up path showed the one-step transition feature. The c-Met DFG flipping mechanism and the new intermediate state discovered in this work could provide a deeper understanding of the conformation-activity relationship for c-Met and, possibly, reveal a new conformational state as the drug target for c-Met and other similar kinases.

HO-1 Limits the Efficacy of Vemurafenib/PLX4032 in BRAFV600E Mutated Melanoma Cells Adapted to Physiological Normoxia or Hypoxia

Induction of heme oxygenase 1 (HO-1) favors immune-escape in BRAF^V600 melanoma cells treated with Vemurafenib/PLX4032 under standard cell culture conditions. However, the oxygen tension under standard culture conditions (~18 kPa O₂) is significantly higher than the physiological oxygen levels encountered in vivo. In addition, cancer cells in vivo are often modified by hypoxia. In this study, MeOV-1 primary melanoma cells bearing the BRAF^V600E mutation, were adapted to either 5 kPa O₂ (physiological normoxia) or 1 kPa O₂ (hypoxia) and then exposed to 10 μM PLX4032. PLX4032 abolished ERK phosphorylation, reduced Bach1 expression and increased HO-1 levels independent of pericellular O₂ tension. Moreover, cell viability was significantly reduced further in cells exposed to PLX4032 plus Tin mesoporphyrin IX, a HO-1 inhibitor. Notably, our findings provide the first evidence that HO-1 inhibition in combination with PLX4032 under physiological oxygen tension and hypoxia restores and increases the expression of the NK ligands ULBP3 and B7H6 compared to cells exposed to PLX4032 alone. Interestingly, although silencing NRF2 prevented PLX4032 induction of HO-1, other NRF2 targeted genes were unaffected, highlighting a pivotal role of HO-1 in melanoma resistance and immune escape. The present findings may enhance translation and highlight the potential of the HO-1 inhibitors in the therapy of BRAF^V600 melanomas.

Combination of Anti-Angiogenics and Checkpoint Inhibitors for Renal Cell Carcinoma: Is the Whole Greater Than the Sum of Its Parts?

Simple Summary

Checkpoint inhibitors and anti-angiogenic therapies are treatments that slow the progression of renal cell carcinoma, the most common type of kidney cancer. Checkpoint inhibitors and anti-angiogenic therapies work in different ways. Checkpoint inhibitors help to prevent tumors from hiding from the body’s immune system, while anti-angiogenic therapies slow the development of blood vessels that tumours need to help them to grow. Studies have shown that treatment with combination checkpoint inhibitor plus anti-angiogenic therapy can achieve better outcomes for patients with renal cell carcinoma than treatment with anti-angiogenic therapy alone. In this review, we consider how combination checkpoint inhibitor plus anti-angiogenic therapy works, and we review the current literature to identify evidence to inform clinicians as to the most effective way to use these different types of drugs, either one after the other, or together, for maximum patient benefit.

Abstract

Anti-angiogenic agents, such as vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitors and anti-VEGF antibodies, and immune checkpoint inhibitors (CPIs) are standard treatments for advanced renal cell carcinoma (aRCC). In the past, these agents were administered as sequential monotherapies. Recently, combinations of anti-angiogenic agents and CPIs have been approved for the treatment of aRCC, based on evidence that they provide superior efficacy when compared with sunitinib monotherapy. Here we explore the possible mechanisms of action of these combinations, including a review of relevant preclinical data and clinical evidence in patients with aRCC. We also ask whether the benefit is additive or synergistic, and, thus, whether concomitant administration is preferred over sequential monotherapy. Further research is needed to understand how combinations of anti-angiogenic agents with CPIs compare with CPI monotherapy or combination therapy (e.g., nivolumab and ipilimumab), and whether the long-term benefit observed in a subset of patients treated with CPI combinations will also be realised in patients treated with an anti-angiogenic therapy and a CPI. Additional research is also needed to establish whether other elements of the tumour microenvironment also need to be targeted to optimise treatment efficacy, and to identify biomarkers of response to inform personalised treatment using combination therapies.

Combination strategies with PD-1/PD-L1 blockade: current advances and future directions

Antibodies targeting programmed cell death protein-1 (PD-1) or its ligand PD-L1 rescue T cells from exhausted status and revive immune response against cancer cells. Based on the immense success in clinical trials, ten α-PD-1 (nivolumab, pembrolizumab, cemiplimab, sintilimab, camrelizumab, toripalimab, tislelizumab, zimberelimab, prolgolimab, and dostarlimab) and three α-PD-L1 antibodies (atezolizumab, durvalumab, and avelumab) have been approved for various types of cancers. Nevertheless, the low response rate of α-PD-1/PD-L1 therapy remains to be resolved. For most cancer patients, PD-1/PD-L1 pathway is not the sole speed-limiting factor of antitumor immunity, and it is insufficient to motivate effective antitumor immune response by blocking PD-1/PD-L1 axis. It has been validated that some combination therapies, including α-PD-1/PD-L1 plus chemotherapy, radiotherapy, angiogenesis inhibitors, targeted therapy, other immune checkpoint inhibitors, agonists of the co-stimulatory molecule, stimulator of interferon genes agonists, fecal microbiota transplantation, epigenetic modulators, or metabolic modulators, have superior antitumor efficacies and higher response rates. Moreover, bifunctional or bispecific antibodies containing α-PD-1/PD-L1 moiety also elicited more potent antitumor activity. These combination strategies simultaneously boost multiple processes in cancer-immunity cycle, remove immunosuppressive brakes, and orchestrate an immunosupportive tumor microenvironment. In this review, we summarized the synergistic antitumor efficacies and mechanisms of α-PD-1/PD-L1 in combination with other therapies. Moreover, we focused on the advances of α-PD-1/PD-L1-based immunomodulatory strategies in clinical studies. Given the heterogeneity across patients and cancer types, individualized combination selection could improve the effects of α-PD-1/PD-L1-based immunomodulatory strategies and relieve treatment resistance.

The Emerging Role of c-Met in Carcinogenesis and Clinical Implications as a Possible Therapeutic Target

Background

c-MET is a receptor tyrosine kinase receptor (RTK) for the hepatocyte growth factor (HGF). The binding of HGF to c-MET regulates several cellular functions: differentiation, proliferation, epithelial cell motility, angiogenesis, and epithelial-mesenchymal transition (EMT). Moreover, it is known to be involved in carcinogenesis. Comprehension of HGF-c-MET signaling pathway might have important clinical consequences allowing to predict prognosis, response to treatment, and survival rates based on its expression and dysregulation. Discussion. c-MET represents a useful molecular target for novel engineered drugs. Several clinical trials are underway for various solid tumors and the development of new specific monoclonal antibodies depends on the recent knowledge about the definite c-MET role in each different malignance. Recent clinical trials based on c-MET molecular targets result in good safety profile and represent a promising therapeutic strategy for solid cancers, in monotherapy or in combination with other target drugs.

Conclusion

The list of cell surface receptors crosslinking with the c-MET signaling is constantly growing, highlighting the importance of this pathway for personalized target therapy. Research on the combination of c-MET inhibitors with other drugs will hopefully lead to discovery of new effective treatment options.

A Combination therapy using an mTOR inhibitor and Honokiol effectively induces autophagy through the modulation of AXL and Rubicon in renal cancer cells and restricts renal tumor growth following organ transplantation

Development of cancer, including renal cancer, is a major problem in immunosuppressed patients. The mTOR inhibitor Rapamycin (RAPA) is used as an immunosuppressive agent in patients with organ transplants and other immunological disorders; and it also has antitumorigenic potential. However, long-term use of RAPA causes reactivation of Akt, and ultimately leads to enhanced tumor growth. Honokiol (HNK) is a natural compound, which possesses both anti-inflammatory and antitumorigenic properties. In this study, we investigated the effect of a novel combination therapy using RAPA + HNK on allograft survival and post-transplantation renal tumor growth. We observed that it effectively modulated the expression of some key regulatory molecules (like Carabin, an endogenous Ras inhibitor; and Rubicon, a negative regulator of autophagy) that play important roles in tumor cell growth and survival. This combination induced toxic autophagy and apoptosis to promote cancer cell death; and was associated with a reduced expression of the tumor-promoting receptor tyrosine kinase AXL. Finally, we utilized a novel murine model to examine the effect of RAPA + HNK on post-transplantation renal tumor growth. The combination treatment prolonged the allograft survival and significantly inhibited post-transplantation tumor growth. It was associated with reduced tumor expression of Rubicon and the cytoprotective/antioxidant heme oxygenase-1 to overcome therapeutic resistance. It also downregulated the coinhibitory programmed death-1 ligand, which plays major role(s) in the immune escape of tumor cells. Together, this combination treatment has a great potential to restrict renal tumor growth in transplant recipients as well as other immunosuppressed patients.

Roles of MET in human cancer

The MET proto-oncogene was first identified in osteosarcoma cells exposed to carcinogens. Although expressed in many normal cells, MET is overexpressed in many human cancers. MET is involved in the initiation and development of various human cancers and mediates proliferation, migration and invasion. Accordingly, MET has been successfully used as a biomarker for diagnosis and prognosis, survival, post-operative recurrence, risk assessment and pathologic grading, as well as a therapeutic target. In addition, recent work indicates that inhibition of MET expression and function has potential clinical benefit. This review summarizes the role, mechanism, and clinical significance of MET in the formation and development of human cancer.

Cabozantinib plus immunotherapy combinations in metastatic renal cell and urothelial carcinoma

Treatment options for metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC) have increased dramatically over the past decade. However, even when novel approaches have proven to be effective as monotherapy, many patients still develop progressive disease, and different strategies are needed to increase clinical response and quality of life. Strategies combining targeted therapy (TT) and immunotherapy (IO) have emerged as a way to shorten the gap between responders and nonresponders to monotherapy and have reported promising results. In this review, we discuss the current role of cabozantinib in combination with IO agents in the treatment of metastatic RCC and UC and go over future directions in the field.

Experimental and computational modeling for signature and biomarker discovery of renal cell carcinoma progression

BACKGROUND

Renal Cell Carcinoma (RCC) is difficult to treat with 5-year survival rate of 10% in metastatic patients. Main reasons of therapy failure are lack of validated biomarkers and scarce knowledge of the biological processes occurring during RCC progression. Thus, the investigation of mechanisms regulating RCC progression is fundamental to improve RCC therapy.

METHODS

In order to identify molecular markers and gene processes involved in the steps of RCC progression, we generated several cell lines of higher aggressiveness by serially passaging mouse renal cancer RENCA cells in mice and, concomitantly, performed functional genomics analysis of the cells. Multiple cell lines depicting the major steps of tumor progression (including primary tumor growth, survival in the blood circulation and metastatic spread) were generated and analyzed by large-scale transcriptome, genome and methylome analyses. Furthermore, we performed clinical correlations of our datasets. Finally we conducted a computational analysis for predicting the time to relapse based on our molecular data.

RESULTS

Through in vivo passaging, RENCA cells showed increased aggressiveness by reducing mice survival, enhancing primary tumor growth and lung metastases formation. In addition, transcriptome and methylome analyses showed distinct clustering of the cell lines without genomic variation. Distinct signatures of tumor aggressiveness were revealed and validated in different patient cohorts. In particular, we identified SAA2 and CFB as soluble prognostic and predictive biomarkers of the therapeutic response. Machine learning and mathematical modeling confirmed the importance of CFB and SAA2 together, which had the highest impact on distant metastasis-free survival. From these data sets, a computational model predicting tumor progression and relapse was developed and validated. These results are of great translational significance.

CONCLUSION

A combination of experimental and mathematical modeling was able to generate meaningful data for the prediction of the clinical evolution of RCC.

New approaches to first-line treatment of advanced renal cell carcinoma

The treatment of patients with renal cell carcinoma (RCC) is evolving rapidly, with promising new regimens being developed and approved for patients with advanced disease, particularly the combination of tyrosine kinase inhibitors with immune checkpoint inhibitors. Within the last 6 months, favorable first-line setting results for patients with clear cell RCC have been reported for the combination of cabozantinib plus nivolumab in the phase III CheckMate 9ER study, leading to its regulatory approval, and lenvatinib plus pembrolizumab in the phase III CLEAR study. Additional systemic first-line treatments for clear cell RCC include axitinib plus pembrolizumab, pazopanib, and sunitinib for favorable-risk patients and ipilimumab plus nivolumab, axitinib plus pembrolizumab, axitinib plus avelumab, and cabozantinib for intermediate- or poor-risk patients. In this review of novel approaches for first-line treatment of advanced RCC, we present an overview of current treatment strategies, the basis behind emerging treatment approaches, a summary of key results from the pivotal studies using tyrosine kinase inhibitor and immune checkpoint inhibitor combination therapy, novel treatments and strategies under development, and efforts for identifying biomarkers to guide treatment decisions.

[Pharmacological properties and clinical outcomes of the anti-cancer drug, cabozantinib (CABOMETYX®)]

Cabozantinib (CAB) is a receptor tyrosine kinase inhibitor with activity against MET, VEGFR2, and AXL, among others. This drug is considered to exert excellent antitumor effects by inhibiting these targets simultaneously. Significant improvement in the primary endpoint (overall survival or PFS) were observed in patients on CAB in comparison with controls in a phase-III study in patients with renal cell carcinoma, progressed after treatment with anti-angiogenic agents, and in another phase-III study in patients with previously treated, advanced hepatocellular carcinoma. These results led to the approval of CAB in Japan in 2020 as a therapeutic agent for unresectable or metastatic renal cell carcinoma and unresectable hepatocellular carcinoma progressed after cancer chemotherapy, under the trade name of CABOMETYX^® (20 mg, and 60 mg tablets). It has been suggested that CAB may modulate the immune system in favor of antitumor immunity and combined use with PD-1 checkpoint inhibitors may exert a synergistic effect. In a phase-III study that examined the efficacy of combination therapy with CAB and nivolumab in treatment-naive patients with advanced renal cell carcinoma, progression-free survival was significantly increased in patients on combination therapy over patients on sunitinib monotherapy. Three global phase-III clinical studies of combination therapy with atezolizumab and CAB in patients with non-small cell lung cancer, castration-resistant prostate cancer, and renal cell carcinoma, are in progress to confirm the efficacy of CAB.

PD-1/PD-L1 inhibitors-based treatment for advanced renal cell carcinoma: Mechanisms affecting efficacy and combination therapies

With the widespread use of PD-1/PD-L1 monoclonal antibodies (mAbs) in the treatment of multiple malignant tumors, they were also gradually applied to advanced renal cell carcinoma (aRCC). Nowadays, multiple PD-1/PD-L1 mAbs, such as nivolumab, avelumab, and pembrolizumab, have achieved considerable efficacy in clinical trials. However, due to the primary, adaptive, and acquired resistance to these mAbs, the efficacy of this immunotherapy is not satisfactory. Theories also vary as to why the difference in efficacy occurs. The alterations of PD-L1 expression and the interference of cellular immunity may affect the efficacy. These mechanisms demand to be revealed to achieve a sustained and complete objective response in patients with aRCC. Tyrosine kinase inhibitors have been proven to have synergistic mechanisms with PD-1/PD-L1 mAb in the treatment of aRCC, and CTLA-4 mAb has been shown to have a non-redundant effect with PD-1/PD-L1 mAb to enhance efficacy. Although combinations with targeted agents or other checkpoint mAbs have yielded enhanced clinical outcomes in multiple clinical trials nowadays, the potential of PD-1/PD-L1 mAbs still has a large development space. More potential mechanisms that affect the efficacy demand to be developed and transformed into the clinical treatment of aRCC to search for possible combination regimens. We elucidate these mechanisms in RCC and present existing combination therapies applied in clinical trials. This may help physicians' select treatment options for patients with refractory kidney cancer.

Linking Immunity with Genomics in Sarcomas: Is Genomic Complexity an Immunogenic Trigger?

Sarcomas comprise a collection of highly heterogeneous malignancies that can be grossly grouped in the categories of sarcomas with simple or complex genomes. Since the outcome for most sarcoma patients has barely improved in the last decades, there is an urgent need for improved therapies. Immunotherapy, and especially T cell checkpoint blockade, has recently been a game-changer in cancer therapy as it produced significant and durable treatment responses in several cancer types. Currently, only a small fraction of sarcoma patients benefit from immunotherapy, supposedly due to a general lack of somatically mutated antigens (neoantigens) and spontaneous T cell immunity in most cancers. However, genomic events resulting from chromosomal instability are frequent in sarcomas with complex genomes and could drive immunity in those tumors. Improving our understanding of the mechanisms that shape the immune landscape of sarcomas will be crucial to overcoming the current challenges of sarcoma immunotherapy. This review focuses on what is currently known about the tumor microenvironment in sarcomas and how this relates to their genomic features. Moreover, we discuss novel therapeutic strategies that leverage the tumor microenvironment to increase the clinical efficacy of immunotherapy, and which could provide new avenues for the treatment of sarcomas.

An up-to-date evaluation of cabozantinib for the treatment of renal cell carcinoma

Introduction: In the evolving treatment scenario of metastatic renal cell carcinoma, cabozantinib is gaining increasing attention, presenting as a cornerstone therapy, both as a monotherapy and in combination with immune-checkpoint inhibitors.Areas covered: In this review, the authors explore the role of cabozantinib in the treatment of metastatic clear cell and non-clear cell renal cell carcinoma, presenting data from the most recent clinical trials and investigating ongoing studies. They, furthermore, evaluate the pharmacokinetic, pharmacodynamic, and immunomodulatory effect of cabozantinib, as well as underlining the tolerability profile and patients' quality of life.Expert opinion: Cabozantinib's administration as a single agent is restricted to intermediate- and poor-risk patients (according to IMDC criteria). The further advent of anti-VEGF-receptor tyrosine kinase inhibitors combined with immune checkpoint inhibitor regimens (such as pembrolizumab + axitinib) has allowed to expand the use of cabozantinib, leading to its combination with nivolumab. In the next few years, more information is required to look for the application of cabozantinib-based combinations as a later-line approach in metastatic RCC patients, beside their use in the first-line setting.

Association of PIK3CA mutation and PTEN loss with expression of CD274 (PD-L1) in colorectal carcinoma

Immunotherapy targeting the CD274 (PD-L1)/PDCD1 (PD-1) immune checkpoint axis has emerged as a promising treatment strategy for various cancers. Experimental evidence suggests that phosphatidylinositol-4,5-bisphosphonate 3-kinase (PI3K) signaling may upregulate CD274 expression. Thus, we hypothesized that PIK3CA mutation, PTEN loss, or their combined status might be associated with CD274 overexpression in colorectal carcinoma. We assessed tumor CD274 and PTEN expression by immunohistochemistry and assessed PIK3CA mutation by pyrosequencing in 753 patients among 4,465 incident rectal and colon cancer cases that had occurred in two U.S.-wide prospective cohort studies. To adjust for potential confounders and selection bias due to tissue availability, inverse probability weighted multivariable ordinal logistic regression analyses used the 4,465 cases and tumoral data including microsatellite instability, CpG island methylator phenotype, KRAS and BRAF mutations. PIK3CA mutation and loss of PTEN expression were detected in 111 of 753 cases (15%) and 342 of 585 cases (58%), respectively. Tumor CD274 expression was negative in 306 (41%), low in 195 (26%), and high in 252 (33%) of 753 cases. PTEN loss was associated with CD274 overexpression [multivariable odds ratio (OR) 1.83; 95% confidence interval (CI), 1.22–2.75; P = .004]. PIK3CA mutation was statistically-insignificantly (P = .036 with the stringent alpha level of 0.005) associated with CD274 overexpression (multivariable OR, 1.54; 95% CI, 1.03–2.31). PIK3CA-mutated PTEN-lost tumors (n = 33) showed higher prevalence of CD274-positivity (82%) than PIK3CA-wild-type PTEN-lost tumors (n = 204; 70% CD274-positivity) and PTEN-expressed tumors (n = 147; 50% CD274-positivity) (P = .003). Our findings support the role of PI3K signaling in the CD274/PDCD1 pathway.

Metabolic reprogramming in renal cancer: Events of a metabolic disease

Recent studies have established that tumors can reprogram the pathways involved in nutrient uptake and metabolism to withstand the altered biosynthetic, bioenergetics and redox requirements of cancer cells. This phenomenon is called metabolic reprogramming, which is promoted by the loss of tumor suppressor genes and activation of oncogenes. Because of alterations and perturbations in multiple metabolic pathways, renal cell carcinoma (RCC) is sometimes termed as a "metabolic disease". The majority of metabolic reprogramming in renal cancer is caused by the inactivation of von Hippel-Lindau (VHL) gene and activation of the Ras-PI3K-AKT-mTOR pathway. Hypoxia-inducible factor (HIF) and Myc are other important players in the metabolic reprogramming of RCC. All types of RCCs are associated with reprogramming of glucose and fatty acid metabolism and the tricarboxylic acid (TCA) cycle. Metabolism of glutamine, tryptophan and arginine is also reprogrammed in renal cancer to favor tumor growth and oncogenesis. Together, understanding these modifications or reprogramming of the metabolic pathways in detail offer ample opportunities for the development of new therapeutic targets and strategies, discovery of biomarkers and identification of effective tumor detection methods.

KEAP1/NRF2 (NFE2L2) mutations in NSCLC - Fuel for a superresistant phenotype?

The transcription factor NRF2 (nuclear factor E2-related factor 2) (also known as nuclear factor, erythroid 2 like 2 [NFE2L2]) is the master regulator of cellular antioxidant responses. NRF2 is repressed by interaction with a redox-sensitive protein KEAP1 (Kelch-like ECH-associated protein 1). Dysregulation of KEAP1/NRF2 transcriptional activity has been associated with the pathogenesis of multiple diseases, and the KEAP1/NRF2 axis has emerged to be the most important modulator of cellular homeostasis. Oxidative stress plays an important role in the initiation and progression of many chronic diseases, including diabetes, cancer, and neurodegenerative diseases. Although its role in immunotherapy is still somewhat controversial, it is well documented from clinical studies that KEAP1/NRF2 mutations in NSCLCs are associated with resistance to various cancer treatments including chemotherapy, X-irradiation, TKI treatment, and a shorter OS and currently available results from clinical trials suggest that KEAP1/NRF2 mutations can be used as a prognostic biomarker (poorer prognosis) for determining prognosis following immunotherapy and a predictive marker for chemo-, radio-, immunotherapy- and TKI-resistance. Despite overwhelming enthusiasm about the various KEAP1/NRF2 inhibitors that have been described during the last decades, none of these inhibitors are currently explored in clinical trials or in clinical applications which clearly add weight to the proposal that the development of these inhibitors remains challenging, but will be beneficial for novel treatment approaches in NSCLC in the near future. In this review we highlight the molecular features, the key components, and possible inhibitors of the KEAP1/NRF2 pathway, its role as prognostic and predictive biomarker, and the resulting clinical implications in NSCLC patients.

HAI-1 is an independent predictor of lung cancer mortality and is required for M1 macrophage polarization

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. Though immune checkpoint inhibitors (ICIs) have revolutionized lung cancer therapy in recent years, there are several factors limiting the therapeutic efficacy of ICI-based immunotherapy in lung cancer. Recent evidence suggests that one such mechanism is the phenotypic shift of tumor-infiltrating macrophages away from an anti-tumor M1 phenotype and towards an anti-inflammatory and tumor-permissive M2 phenotype. Though this phenomenon is well documented, the means through which the lung tumor microenvironment (TME) usurps macrophage function are poorly described. Hepatocyte growth factor (HGF) is a known driver of both lung cancer pathobiology as well as M2 polarization, and its signaling is antagonized by the tumor suppressor gene HAI-1 (SPINT1). Using a combination of genomic databases, primary NSCLC specimens, and in vitro models, we determined that patients with loss of HAI-1 have a particularly poor prognosis, hallmarked by increased HGF expression and an M2-dominant immune infiltrate. Similarly, conditioned media from HAI-1-deficient tumor cells led to a loss of M1 and increased M2 polarization in vitro, and patient NSCLC tissues with loss of HAI-1 showed a similar loss of M1 macrophages. Combined, these results suggest that loss of HAI-1 is a potential means through which tumors acquire an immunosuppressive, M2-dominated TME, potentially through impaired M1 macrophage polarization. Hence, HAI-1 status may be informative when stratifying patients that may benefit from therapies targeting the HGF pathway, particularly as an adjuvant to ICI-based immunotherapy.

Has programmed cell death ligand-1 MET an accomplice in non-small cell lung cancer?-a narrative review

Recently approved and highly specific small-molecule inhibitors of c-MET exon 14 skipping mutations (e.g., capmatinib, tepotinib) are a new and important therapeutic option for the treatment of non-small cell lung cancer (NSCLC) patients harbouring c-MET alterations. Several experimental studies have provided compelling evidence that c-MET is involved in the regulation of the immune response by up-regulating inhibitory molecules (e.g., PD-L1) and down-regulating of immune stimulators (e.g., CD137, CD252, CD70, etc.). In addition, c-MET was found to be implicated in the regulation of the inflamed tumour microenvironment (TME) and thereby contributing to an increased immune escape of tumour cells from T cell killing. Moreover, it is a major resistance mechanism following treatment of epidermal growth factor receptor mutations (EGFRmut) with tyrosine kinase receptor inhibitors (TKIs). In line with these findings c-MET alterations have also been shown to be associated with a worse clinical outcome and a poorer prognosis in NSCLC patients. However, the underlying mechanisms for these experimental observations are neither fully evaluated nor conclusive, but clearly multifactorial and most likely tumour-specific. In this regard the clinical efficacy of checkpoint inhibitors (CPIs) and TKIs against EGFRmut in NSCLC patients harbouring c-MET alterations is also not yet established, and further research will certainly provide some guidance as to optimally utilise CPIs and c-MET inhibitors in the future.

Combined with interventional therapy, immunotherapy can create a new outlook for tumor treatment

Recent progress in immunotherapy provides hope of a complete cure to cancer patients. However, recent studies have reported that only a limited number of cancer patients with a specific immune status, known as "cold tumor", can benefit from a single immune agent. Although the combination of immune agents with different mechanisms can partially increase the low response rate and improve efficacy, it can also result in more side effects. Therefore, discovering therapies that can improve tumors' response rate to immunotherapy without increasing toxicity for patients is urgently needed. Tumor interventional therapy is promising. It mainly includes transcatheter arterial chemoembolization, ablation, radioactive particle internal irradiation, and photodynamic interventional therapy based on a luminal stent. Interventional therapy can directly kill tumor cells by targeted drug delivery in situ, thus reducing drug dosage and systemic toxicity like cytokine release syndrome. More importantly, interventional therapy can regulate the immune system through numerous mechanisms, making it a suitable choice for immunotherapy to combine with. In this review, we provide a brief description of immunotherapies (and their side effects) on tumors of different immune types and preliminarily elaborate on interventional therapy mechanisms to improve immune efficacy. We also discuss the progress and challenges of the combination of interventional therapy and immunotherapy.

Combination of molecularly targeted therapies and immune checkpoint inhibitors in the new era of unresectable hepatocellular carcinoma treatment

Multikinase inhibitors (MKIs) have been the only first-line treatment for advanced hepatocellular carcinoma (HCC) for more than a decade, until the approval of immune checkpoint inhibitors (ICIs). Moreover, the combination regimen of atezolizumab (anti-programmed cell death protein ligand 1 antibody) plus bevacizumab (anti-vascular endothelial growth factor monoclonal antibody) has recently been demonstrated to have superior efficacy when compared with sorafenib monotherapy. The remarkable efficacy has made this combination therapy the new standard treatment for advanced HCC. In addition to MKIs, many other molecularly targeted therapies are under investigation, some of which have shown promising results. Therefore, in the era of immuno-oncology, there is a significant rationale for testing the combinations of molecularly targeted therapies and ICIs. Indeed, numerous preclinical and clinical studies have shown the synergic antitumor efficacy of such combinations. In this review, we aim to summarize the current knowledge on the combination of molecularly targeted therapies and immune checkpoint therapies for HCC from both preclinical and clinical perspectives.

Cabozantinib: An evolving therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is rising in incidence and remains a leading cause of cancer-related death. After a decade of disappointing trials following the approval of sorafenib for patients with advanced HCC, a number of tyrosine kinase inhibitors (TKIs) and monoclonal antibodies targeting angiogenesis and immune checkpoints have recently been approved. The phase 3 CELESTIAL trial demonstrated improved progression-free and overall survival with the TKI cabozantinib compared to placebo, supporting it as a treatment option for patients with advanced HCC previously treated with sorafenib. Cabozantinib blocks multiple key pathways of HCC pathogenesis, including VEGFR, MET, and the TAM (TYRO3, AXL, MER) family of receptor kinases, and promotes an immune-permissive tumor microenvironment. Here, we review the mechanisms of action of cabozantinib, including effects on tumor growth and its immunomodulatory properties, providing pre-clinical rationale for combination strategies with checkpoint inhibitors. We discuss the design and outcomes of CELESTIAL including improved survival across subgroups defined by age, disease etiology, baseline AFP level, prior therapies (including duration of prior sorafenib), and tumor burden. Cabozantinib had a manageable safety profile with dose modification. Studies combining cabozantinib with atezolizumab (COSMIC-312) and durvalumab (CAMILLA) in the first and second-line settings are ongoing, as well as a neoadjuvant study of cabozantinib with nivolumab. Future investigations are warranted to define the use of cabozantinib in patients with Child-Pugh B liver function and identify markers predictive of clinical benefit. The role of cabozantinib in HCC continues to evolve with an anticipated role in immunotherapy combinations.